[pulseaudio-discuss] Audio distortions in Iceweasel/Firefox: [alsa-sink] flist.c: pulsecore/memblockq.c: list_items flist is full (don't worry)

[Paul Menzel]

Dear PulseAudio folks,


Am Freitag, den 07.06.2013, 00:42 +0200 schrieb Paul Menzel:

> using Debian Wheezy with Linux 3.2.x and (unfortunately) PulseAudio 2.0,
> 
>         !!DMI Information
>         !!---------------
> 
>         Manufacturer:      ASROCK
>         Product Name:      E350M1
>         Product Version:   1.0
>         Firmware Version:  4.0-4163-g417d992
> 
> 
>         !!Kernel Information
>         !!------------------
> 
>         Kernel release:    3.2.0-4-686-pae
>         Operating System:  GNU/Linux
>         Architecture:      i686
>         Processor:         unknown
>         SMP Enabled:       Yes
> 
> 
>         !!ALSA Version
>         !!------------
> 
>         Driver version:     1.0.24
>         Library version:    1.0.25
>         Utilities version:  1.0.25
> 
> 
> when playing YouTube movie or playing an online stream using
> Iceweasel/Firefox, sound suddenly gets distorted (very high tones and
> *not* understandable anymore. Jumping forward in the stream increases
> chances that this gets triggers. Sometimes pausing and resuming fixes
> this issue but sometimes it does not help at all. I could not reproduce
> this with another application yet.

looking into it, it was easily reproducible by just running
`speaker-test`.

    $ speaker-test -c 2 -t sine

After the channel is switch or when it is repeated the tone would get
distorted.

> When increasing the log level to debug, I get the following messages.
> 
>         $ more /var/log/syslog
>         […]
>         … [alsa-sink] flist.c: pulsecore/memblockq.c: list_items flist is full (don't worry)
>         […]
>         … [alsa-sink] alsa-sink.c: Cutting sleep time for the initial iterations by half.
>         […]
> 
> Please find more verbose logs and the output of `alsa-info.sh` [1]
> attached.
> 
> Does this point to a problem in PulseAudio or the ALSA driver? Or
> something else?

Discussing this in #pulseaudio on <irc.freenode.net> I was told that
this is likely a Linux ALSA driver problem. Taking out the disk and
connecting it to a different board with a Realtek ALC888 audio chip, I
had the same problem though.

Then I installed PulseAudio 4.0-3 from Debian Sid/unstable and the
problem is gone now.

Does that imply, that it was an error in PulseAudio 2.0? Or is
PulseAudio 4.0 able to work around ALSA driver bugs?

> Any help on how to fix this is appreciated a lot as Debian Wheezy is
> going to be the recommended flavor(?) for the next two years and it
> would be nice to get this fixed in there.


Thanks,

Paul


> [1] http://alsa-project.org/main/index.php/Help_To_Debug
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